In order to minimize intra- and post-operative complications from cataract extraction, a surgeon must have the best possible view of intraocular tissue. There may be occasion when a small pupil is encountered, such as with pseudoexfoliation, posterior synechiae, use of miotics, or, uveitis.
If a pupil cannot be properly dilated for cataract extraction, there is risk of: iris damage; incomplete aspiration of lens fragments and cortical material; damage to the posterior capsule; compromised capsulorhexis; loss of vitreous; and, dropped nucleus into the vitreous cavity.
A rise in the incidence of intraoperative floppy iris syndrome, or IFIS, has been noted. Cited results from a retrospective and prospective study indicate that IFIS is encountered approximately 2% of the time. (Chang, D. F., Campbell J. R., “Intraoperative Floppy Iris Syndrome Associated With Tamsulosin”, J. Cataract Refract. Surg. 2005; 31: 664-673). Most of the affected patients were found to be taking alpha 1 blockers, such as tamsulosin (“Flomax”), to address benign prostatic hyperplasia. Alpha 1 blockers may cause the iris dilator muscle to relax which makes pupil dilation difficult.
Treatments prior to cataract extraction may include: a pharmacological approach (NSAID's, preservative-free epinephrine, viscoelastic substances); mechanical manipulation (iris hooks/retractors, iris rings/dilators); and, iris surgery.